Automatic spark control



June 15, 1937. H. w. MEADE AUTOMATIC SPARK CONTROL Filed Oct. 25, 1933 5 Sheets-Sheet l m w M m E0 O V W N rMW June 15, w MEADE AUTOMATIC SPARK CONTROL Filed Oct. 25, 1933 '5 Sheets-Sheet 2 5253:. 1-351 FIZZ? l l I 2.2 24 i V ii 62' an 28' E 5 28 Harold \M Meade, INVENTOR.

ATTORNEY,

June 15, 1937. H. w. MEADE 2,084,158

AUTOMATIC SPARK CONTROL Filed Oct. 25, 1953 3 Sheets-Sheet 5 F ST" Harold W, M d INVENTOR.

In a $4 .6;

ATTORNEY.

Patented June 15, 1937 STAT ants

eA'rEr iee 7 Claims.

My invention relates to improvements in auto matic spark control mechanisms. The object of my invention is to produce a device which will vary the spark setting in accordance with the load on the engine, in general advancing the spark as the load decreases and retarding the spark as the load increases. Such device may be used alone or in conjunction with other spark control means.

Further it is my object to produce a device which will retard the spark when the load on the engine decreases to an idling load and yet be adapted to again advance the spark when a negative load exists on the engine, as in the case when the momentum of the fly wheel, or motor car, turns the engine at a speed in excess of its pulling speed.

A further object of my invention is to provide means whereby the fuel mixture to the engine can be varied in general as the load on the engine varies.

Other objects of my invention will be pointed out in the specification.

Referring to the drawings which show the proposed form of my invention:

Fig. 1 illustrates a half sectional view of the device for controlling the efiect of the vacuum during no load conditions.

Fig. 2 illustrates the general assembly.

Fig. 3 is a fragmental sectional illustration of a modification of Fig. 1.

Fig. 4 illustrates a manner of obtaining vacuum pressure in the intake conduit.

Fig. 5 illustrates a modified form of the pneu- 35 matic spark control mechanism including means for automatically varying the fuel mixture.

Fig. 6 illustrates a modified manner of attaching the spark control mechanism to the timer.

Fig. '7 is a profile view of Fig. 5.

In the general form of my device illustrated in Fig. 2, l3 represents diagrammatically the timer of an engine, which may include a centrifugal governor or the equivalentthe arrow indicating the direction of rotation for advance of the spark. The cylinder 1 contains a piston connected to the timer on its atmospheric side and subject to pressure existing in the intake manifold on the other side, and so adapted that as the pressure decreases in the intake manifold 50 the piston will be moved to advance the spark against a spring or other resistance tending to hold the timer in a retarded position. The effect of the vacuum pressure in the intake manifold on the pressure responsive element 7 is varied by 55 the device 4 of Fig. 2 and also illustrated in detail in Fig. 1. The device of Fig. l is illustrated in a pneumatically open position, as when the engine is being operated under load, permitting the vacuum existing in conduit 8 by reason of connection to the intake conduit to exercise its normal efiect on the pressure responsive element 7. An increase or decrease in pressure in conduit 8 is communicated through opening 3, through passage 2!, through the compartment 6|, through open valve 3 I, through passages l 8, 23 and 36 and opening 6 to pressure responsive element 1.

To illustrate the operation of the device as shown in Fig. 2 consider the pressure responsive element 7 in a retarded position owing to the low degree of vacuum existing in conduit 9 as in the case of full throttle engine operation. As the load on theengine is reduced, a higher degree of vacuum exists in conduit 9 thereby influencing pressure responsive element '5 to advance the spark. If the engine is then idled, a further increase in vacuum will occur in conduit 9 of sufficient intensity to bring into operation piston l6 of the device illustrated in Fig. l, which piston is subject to manifold vacuum pressure and to atmospheric pressure through aperture E5.

The degree of vacuum at which piston it will operate is determined by its area and the resistance of spring ll. As piston 15 moves under the influence of the idling vacuum, it engages with valve seat. 3!, thereby closing pass-age i8. Further movements of piston it under the influence of the idling vacuum is communicated through spring 20 to va1ve'25, causing it to recede from its seat. 24 against the resistance of spring 2?, the maximum value of which is less than the tension required to compress loaded spring 26. The opening of valve 25 permits the atmospheric pressure existing in passage 23 to be communicated through open valve 25, passage 33 to the piston in cylinder 7, which will recede to its retarded position under the influence of its spring.

If the load on the engine is then increased the degree of vacuum in the manifold will decrease, permitting the master valve mechanism to return as a unit with piston [6 under the influence of springs 21 and H until valve 25 engages with its seat 24, thereby cutting off communication with the atmosphere. When the manifold vacuum decreases and piston It returns furthenit recedes from 3|, thereby opening direct communication from passagezl to passage 36, again subjecting the piston in cylinder '7 to the direct influence of thevacuum existing in the intake conduit.

While it is desirable to provide for a retarded During idling, passage I8 is closed by the contact of piston |6 on valve seat 3| and valve is disengaged from its seat 24 and the piston in cylinder '1 is in its retarded position as above illustrated. When a still higher degree of vacuum exists in the intake manifold, as in the case when the engine is being used as a brake, piston |6 will move master valve mechanism as a unit until valve 26 closes passage 28. Upon engagement of valve 26 with its seat 62 the excessively high vacuum exerts additional pressure on springs l1,

and 20 thereby opening valve '33. The closing of passage 28 prevents the communication of 'atmospheric pressure to the piston of cylinder 1 and the opening of valve 33 subjects the said piston to the high manifold vacuum existing in passage 2|. This will result in the advance of the spark so long as such high vacuum condition is continued in the intake manifold.

Tosecure the opening and closing at the same pressure of the valve formed by piston l6 and with its valve seat 3|, it is desirable to have the area of valve seat 24 equal to the area of the portion of the piston l6 covered by its valve seat 3|. It may also be desirable for similar reasons to make the area of valve seat 28 equal to that of 24 as is illustrated in Fig. 3.

Another form of my invention is illustrated by Figs. 5, 6 and 7. In Fig. 6, I3 represents a timer, the arrow of timer |3 indicates the direction of rotation for advance of the spark. Bracket 56 is mounted in some fixed position on the engine in such a position as to tend to hold the timer in a retarded position by spring 54. Piston 63 of Fig. 5 is operatively connected to the timer |3 through linkage 48 and 64. Passage 2| is connected by tubing to the throat of the intake manifold so that piston 63 is subject to the influence of the vacuum in said intake manifold because of direct communication through passages 2|, 6| and 36. During operation the piston 63 is moved toward the left as the degree of vacuum increases.

Within the passage connecting the interior of easing with the intake manifold 9 there is a valve which will be closed when the pressure on the engine side of the throttle drops below a predetermined minimum. To accomplish this end I preferably form valve seat 65 in this passage. With this valve seat 65 there co-operates a valve in the form of a piston I6. portion thereof formed into a dashpot to damp any oscillation of the piston. The piston valve i6 communicates with the atmosphere through vent I5. I

The spring H is so adjusted that at the degree of vacuum existing at idling speed the piston valve l6 will engage valve seat 65 thereby preventing the high manifold vacuumpresent in passage 2| from exerting its influence on piston 63. The pressure in casing 1 becomes atmospheric through passages 53,52, 56 and 66 thereby retarding the spark.

Fig. 7 illustrates the end view of base 59. and 68 are openings through 59, permitting communication of the atmosphere to the interior of chamber 61. The passage 50 together with inlet 52 and passage 53 form a means of communication between compartments 6! and 68 on the opposite side of piston 63. When piston 63 is in The piston has a position of the throttle.

an advanced position and valve I6 is closed because of idling vacuum, such passages form an air bleed through piston 63 and permit it to return to a retarded position under the influence of spring 54. When valve I6 is open there is a flow of air through said passage 53 to chamber 68 and from there through passages 36 and 2| to the intake manifold. This dilutes or leans the gasoline mixture reaching the cylinder of the engine. As it is undesirable for the engine to receive as lean a mixture when the engine is operating under heavy load, piston rod 66 is grooved at point 5| to form a valve with passage 5|]; the piston rod 66 cutting off passage 50 when piston 63 is in a retarded position. This prevents communication between passages 50 and 53, thereby preventing any flow of air to the intake manifold. Set screw 4! provides means for regulating the amount of air which will flow through passage 50, to the intake manifold.

The embodiment of my invention which has just been described consists of a single connection from the pressure-responsive element to the engine intake passage. Preferably, the above structure is to be used in combination with an additional element, such as a centrifugal governor,

to advance the spark. If it is not desired to use the centrifugal governor, or a similar device, a pneumatic equivalent maybe used instead. Such a construction is illustrated in Fig. 4.

This device embodies two separate connections to the intake conduit. The connection between the engine and the throttle may be extended into the intake conduit in such a manner that flow of air will produce an impact pressure at mouth of extension of tube 40. equivalent, will have greater pressure in tube 4| than the normal static pressure at the same point, except when the throttle is closed or nearly closed.

As the impact pressure is very small at closed Such a structure, or its throttle positions even though the velocity may be rather high, the result is that scope of pressure change is greater, thereby permitting a more selective functioning of piston va1ve l6. A venturi 39 may be placed in intake conduit to augment the velocity of flow;

The second connection into the intake conduit may be a tube 43 which is located at a'point between inlet of the intake conduit and the throttle. Preferably such a connection is made at a point in the passage of the venturi 38 beyond and on."

the downstream side of the throat thereof where the velocity of air flow induces a reduction in pressure in addition to the reduced static pressure of the moving column of air.

The vacuum produced under these conditions may be several times as great as the static pressure of the column of flowing air existing at the throat of venturi 38.

For any given position of the throttle, the velocity of flow of air through the venturiv 38 will vary, substantially as the speed of engine, within the limitation of the capacity determined by the "er interval of time between pulsations results in less advance of the spark than would otherwise occur. It is well understood that several factors affect the quantity of charge that will be supplied to the engine compared to the piston displacement. The volumetric efliciency decreasing If the throttleis fully The vacuum pressures hereby the relative amount of charge supplied to the engine constitutes a desirable modification of increments of the degrees of vacuum, occurring at mouth of tube 43. As the degree of vacuum induced at points in the venturi 38, by the kinetic energy of the moving column of air, may be greatly in excess of the static pressure causing flow of air, the result is improved co-ordination with the pressures occurring between the engine and the throttle.

This improved co-ordination, between the pres-- sures existing respectively in the intake conduit, between the engine and the throttle and between the inlet of said conduit and said throttle, results in greater advances'of the spark under heavy load conditions and slow speeds.

The tendency of timer-regulating means, controlled solely by intake conduit pressures, is to give excessive retards of the spark under full load conditions at slow speeds. It is my object to provide means for overcoming this condition. This means may be used alone or in conjunction with other means tending to correct this undesirable condition. The use of the impact pressures at points between the engine and the throttle to decrease the degree of vacuum occurring therein also is a means that may be used to produce a similar result. Specifically, this is accomplished by rendering the pressure-responsive element more sensitive, the impact pressures preventing excessive advance of the spark under light load conditions.

I claim as my invention:

1. In combination with an internal combustion engine, an air and fuel supply conduit therefor, a throttle valve in said conduit, timer-regulating means controlled by fluid pressures existing in said conduit between the throttle and the engine so adapted. as to vary the spark setting during normal load conditions of the engine as said fluid pressures vary; to retard the spark when said fluid pressure decreases to a predetermined value as during idling and to advance the spark when said fluid pressure decreases to a greater extent as when the engine is being used as a brake.

2. In combination with an internal combustion engine, an air and fuel supply conduit therefor, a throttle valve in said conduit, timer-regulating means controlled by fluid pressures existing in said conduit between the throttle and the engine so adapted as to retard the spark when said fluid pressure decreases to a predetermined value as during idling and to advance the spark when said fluid pressure decreases to a greater extent as when the engine is being used as a brake.

3. In combination with an internal combustion engine, an air and fuel supply conduit therefor, a throttle valve in said conduit, timer-regulating means controlled by pressures existing in said conduit between the throttle and the engine so adapted as to vary the spark setting during normal load conditions of the engine as said pressures vary; to retard the spark when said pressure decreases to a predetermined value as during idling and to advance the spark when said pressure decreases. to a greater extent as when the engine is being used as a brake without continuous flow of air caused by said timer-regulating means to the intake manifold.

4. In combination with an internal combustion engine, an air and fuel supply conduit therefor, a throttle valve in said conduit, timer-regulating means connected to said conduit between the engine and said throttle and normally operative to advance the spark upon decreasing pressure within said conduit, and pressure affected means having valves operated by a predetermined pressure in said conduit to open and close at the same predetermined pressures for submitting said timer-regulating means to the influence of atmospheric pressure instead of pressures in said conduit.

5. In combination with an internal combustion engine, an air and fuel supply conduit therefor, a throttle valve in said conduit, timer-regulating means connected to said conduit between the engine and said throttle and normally operative to advance the spark upon decreasing pressure within said conduit, and automatic means comprising valves of equal area operated by a predetermined pressure in said conduit for submitting said timer-regulating means to the influence of atmospheric pressure instead of pressures in said conduit, said automatic means being adapted to again submit said timer-regulating means to pressures in said conduit instead of atmospheric pressure when the pressure in said conduit again exceeds said. predetermined pressure.

6. In combination with an internal combustion engine, an air and fuel supply conduit therefor, a throttle valve in said conduit, timer-regulating means connected to said conduit between the engine and said throttle and normally operative to advance the spark upon decreasing pressure within said conduit, and means comprising valves having no lost motion in their sequence of operation for successively, at predetermined pressures, cutting ofi the suction and admitting the atmospheric pressure, thereby rendering said pressure within said conduit inoperative to influence the timer-regulating means.

7. In combination with an internal combustion engine, an air and fuel supply conduit therefor, a throttle valve in said conduit, timer-regulating means including a control piston having a single connection to said conduit between the throttle and the engine so adapted as tovary the spark setting during normal load conditions of the engine as said pressures vary; to retard the spark when said pressure decreases to a predetermined value as during idling, and to permit an automatically controlled air flow through the control piston and said connect-ion to the intake manifold.

HAROLD W. MEADE. 

